about mpfi system in petrol cars?

Question

like oxygen sensors which is fitted with exhaust mani fold

Answer 1

multi point fuel injection system.

Answer 2

MPFI stands for multi-PORT-fuel injected. If your oxygen sensor light comes on, it won't go off until somebody who knows how to reset it, resets it. Like your local dealership service department, who are basically trying to get you to come back in and lay a bunch more so-called needed repairs on you while you're there. Try to find a mechanic friend who has a little palm diagnostic computer that can reset it to turn it off. If you don't know people (mechanics) in high places, the price can be rather high. Actually? If you can stand it, just ignore the damn idiot light. It will not hurt your car or you, maybe your eyes and your nerves but that is about it. One thing for sure though, it has to be replaced before you get the car smogged, or it will not pass smog. They're all in it together, I tell yah! LOL! :)

Answer 3

Fundamentals of Fuel Injection

‘Mpfi’ stands for 'multi point (electronic) fuel injection'. This system injects fuel into individual cylinders, based on commands from the ‘on board engine management system computer’ – popularly known as the Engine Control Unit/ECU.

Mpfi Systems can either be : a) ‘Sequential’ i.e direct injection into individual cylinders against their suction strokes, or b) ‘Simultaneous’ i.e together

for all the four or whatever the number of cylinders, or c) ‘Group’ i.e into Cylinder-Pairs.

These techniques result not only in better ‘power balance’ amongst the cylinders but also in higher output from each one of them, along with faster throttle response.

Of these variants of Mpfi, 'Sequential' is the best from the above considerations of power balance/output.

‘Sefi’’, as advertised by Ford Ikon, stands for 'Sequential Electronic Fuel Injection', which technically is the best of the above variants of Mpfi. Hyundai/Maruti Mpfi systems are in fact Sefi too. Daewoo India had the (b) or (c) variants of above Mpfi systems on its Cielo/Matiz.

On the other hand, older Opel-Astra’s had a 'single point' fuel injection system, which is in between an Mpfi and the now obsolete Single-Carburettor systems.

The ‘Fuel Injectors’ are precision built ‘Solenoid Valves’, something like Washing Machine Water inlet Valves. These have either single or multiple ‘Orifices’ which ‘spray’ fuel into the Fuel inlet manifold of a Cylinder upon actuation, from a common Rail/Header pressurised to around 3 bar, fed by a high pressure electrically drive fuel pump inside the Petrol tank of the Car.

The ‘on-board’ ECU primarily controls the Ignition Timing and quantity of fuel to be injected. The latter is achieved by means of controlling the ‘duration’ for which the Injector solenoid valve coil is kept energized – popularly known as the ‘pulse-width’.

In general, an ECU in turn is controlled by the ‘data input’ from a set of ‘SENSORS’ located all over the Engine and its Auxiliaries. These detect the various ‘operating states’ of the Engine and the performance desired out of it. Such Sensors constantly monitor : 1) Ambient Temperature, 2) Engine Coolant Temp., 3) Exhaust/manifold temp., 4) Exhaust ‘O2’ content, 5) Inlet manifold vacuum, 6) Throttle position, 7) Engine rpm, 8) Vehicle road speed, 9) Crankshaft position, 10) Camshaft position, etc.

Based on a ‘programmed’ interpretation of all this input data, the ECU gives the various ‘commands’ to the Engine’s fuel intake and spark ignition timing systems, to deliver an overall satisfactory performance of the Engine from start to shut down, including ‘emission control’.

To get the best out of an Mpfi System, one should use – a) The OE recommended Petrol Additives or the new generation ‘Premium’ Petrol’s REGULARLY and b) NEVER Tamper with the OE Wiring Harness of the Car – EVEN to install the ubiquitous Music System OR any other Electrical Accessory - other than those ‘approved’ OE/Dealer and designed to suit the Car’s Wiring Harness/CWH ‘Couplers’.

Answer 4

I too have one on my Maruthi 800car. I too like to the best answer when you get it...